Absorbent medium for carbonic-acid gas.



JOHN, canraan} or. "snenasron, nnerlnnn.

stemming.

To all whom it may concern Be itknown that I, JOHN CADMAN, 'D. So, a subject, of the King of Great Britain, residing at '61 .TvVellington road, Edgbaston,

iVarWickshire, England, have invented a,

newand useful Improved Absorbent Medium for Carbonic-Acid Gas, of which the following is a specification.

-' carbonic acid gas from a1r,ai1d 1t 1s par- This invention relates toimprovements in- Inedia for the elimination or absorption of ticularly designed for use in connection with breathingapparatus used by persons Working in irrespirable atmospheres or under his exhaled breath after it. has been purified of the carbonic acid gas which it contains. It has hitherto been the practice to make use for this purpose of lumps, sticks or granules of causticgsoda, soda lime or caustic potash, over the surface Of-WhlOh the impure air is passed, and it has been found that air so 1 freed of its carbonic acid content becomes unpleasantly hot.' Attempts have been made to remedy this defect by the employment of a cooling device through which the purified air is caused to pass before being rebreathed; v

Now, my invention has for its-object to provide an improved form of. purifyingmeium'for the elimination of carbonic acid g efmm air and to this' end I proceed as thin layer or skin upon a porous vehicle '1 such as coke, charcoal Qor-any other i substancehaving a high" specific heat. I 4 In practice I prefer to employsrualdjulnps ip fcoke which are immersed in melted caustic {followsztha t is to say, in lieu of employin g solid lumps or the equivalent of the ab- .sforbent substance such as caustic soda, I

employ the said substance in the form of a Water and in which the wearer rebreathes pprous I ABsoanEN'r MEDIUM FOR OARBONIC-ACID Gas.

Specification oi. Letters Patent. 1 Patented Dec. 5, 1916. Application filed July 17, 1914. Serial no. 851,667.

soda, caustic potash, soda'lime or the like,

and allowed to remain therein while the latter is kept in motion until a layer film or skin of the alkali has solidified over the surfaces of the lumps. Impure air passed over an absorbent medium as above described is purified by the elimination of the carbonic acid gas it contains Without being unduly heated. As a further safeguard against the heating of the air, however, I may add to the carbonic acid absorbent a' suitable such as'calc ium chlorid.

Claims:

1. A regenerative medium comprising a vehicle consisting of a porous substance such as coke, charcoal or the like, having an exterior and interior coating, film or skin of a carbonic acid gas absorbent. p

2. An absorbent for carbonic acid gas,

,Which consists of a porous vehicle having its entire surface exteriorly and interiorly covered by a coating or film of caustic soda.

3. An absorbent for carbonic acid gas, comprising a vehicle consisting of a porous substance such as coke, charcoal or the like,

cooling material having an exterior and interior coating, film or skin of an absorbent material, to which has been added a substance having greater aifinity for, moisture and less heat of solution than the absorbent material; v

4. An absorbent for carbonic acid gas,

comprising a vehicle which consists of a porous substance, having exterior-1y and in teriorly a coating of a carbonic acid "gas absorbent, to which has been added calcium' chlorid.

. x JOHN CADMAN.

Witnesses: v

JOHN F. SrMoNs,

' ,MU1 2AT H. DAVIDSON. 

